System.Net.WebHeaderCollection The HTTP headers that may be specified in a client request. The Accept header, which specifies the MIME types that are acceptable for the response. The Accept-Charset header, which specifies the character sets that are acceptable for the response. The Accept-Encoding header, which specifies the content encodings that are acceptable for the response. The Accept-Langauge header, which specifies that natural languages that are preferred for the response. The Allow header, which specifies the set of HTTP methods supported. The Authorization header, which specifies the credentials that the client presents in order to authenticate itself to the server. The Cache-Control header, which specifies directives that must be obeyed by all cache control mechanisms along the request/response chain. The Connection header, which specifies options that are desired for a particular connection. The Content-Encoding header, which specifies the encodings that have been applied to the accompanying body data. The Content-Langauge header, which specifies the natural language(s) of the accompanying body data. The Content-Length header, which specifies the length, in bytes, of the accompanying body data. The Content-Location header, which specifies a URI from which the accompanying body may be obtained. The Content-MD5 header, which specifies the MD5 digest of the accompanying body data, for the purpose of providing an end-to-end message integrity check. The Content-Range header, which specifies where in the full body the accompanying partial body data should be applied. The Content-Type header, which specifies the MIME type of the accompanying body data. The Cookie header, which specifies cookie data presented to the server. The Date header, which specifies the date and time at which the request originated. The Expect header, which specifies particular server behaviors that are required by the client. The Expires header, which specifies the date and time after which the accompanying body data should be considered stale. The From header, which specifies an Internet E-mail address for the human user who controls the requesting user agent. The Host header, which specifies the host name and port number of the resource being requested. The If-Match header, which specifies that the requested operation should be performed only if the client's cached copy of the indicated resource is current. The If-Modified-Since header, which specifies that the requested operation should be performed only if the requested resource has been modified since the indicated data and time. The If-None-Match header, which specifies that the requested operation should be performed only if none of client's cached copies of the indicated resources are current. The If-Range header, which specifies that only the specified range of the requested resource should be sent, if the client's cached copy is current. The If-Unmodified-Since header, which specifies that the requested operation should be performed only if the requested resource has not been modified since the indicated date and time. The Keep-Alive header, which specifies a parameter used into order to maintain a persistent connection. The Last-Modified header, which specifies the date and time at which the accompanying body data was last modified. The Max-Forwards header, which specifies an integer indicating the remaining number of times that this request may be forwarded. The Pragma header, which specifies implementation-specific directives that might apply to any agent along the request/response chain. The Proxy-Authorization header, which specifies the credentials that the client presents in order to authenticate itself to a proxy. The Range header, which specifies the the sub-range(s) of the response that the client requests be returned in lieu of the entire response. The Referer header, which specifies the URI of the resource from which the request URI was obtained. The TE header, which specifies the transfer encodings that are acceptable for the response. The Trailer header, which specifies the header fields present in the trailer of a message encoded with chunked transfer-coding. The Transfer-Encoding header, which specifies what (if any) type of transformation that has been applied to the message body. The Translate header, a Microsoft extension to the HTTP specification used in conjunction with WebDAV functionality. The Upgrade header, which specifies additional communications protocols that the client supports. The User-Agent header, which specifies information about the client agent. The Via header, which specifies intermediate protocols to be used by gateway and proxy agents. The Warning header, which specifies additional information about that status or transformation of a message that might not be reflected in the message. The HTTP headers that can be specified in a server response. The Accept-Ranges header, which specifies the range that is accepted by the server. The Age header, which specifies the time, in seconds, since the response was generated by the originating server. The Allow header, which specifies the set of HTTP methods that are supported. The Cache-Control header, which specifies caching directives that must be obeyed by all caching mechanisms along the request/response chain. The Connection header, which specifies options that are desired for a particular connection. The Content-Encoding header, which specifies the encodings that have been applied to the accompanying body data. The Content-Langauge header, which specifies the natural language or languages of the accompanying body data. The Content-Length header, which specifies the length, in bytes, of the accompanying body data. The Content-Location header, which specifies a URI from which the accompanying body can be obtained. The Content-MD5 header, which specifies the MD5 digest of the accompanying body data, for the purpose of providing an end-to-end message integrity check. The Range header, which specifies the subrange or subranges of the response that the client requests be returned in lieu of the entire response. The Content-Type header, which specifies the MIME type of the accompanying body data. The Date header, which specifies the date and time at which the response originated. The Etag header, which specifies the current value for the requested variant. The Expires header, which specifies the date and time after which the accompanying body data should be considered stale. The Keep-Alive header, which specifies a parameter to be used to maintain a persistent connection. The Last-Modified header, which specifies the date and time at which the accompanying body data was last modified. The Location header, which specifies a URI to which the client is redirected to obtain the requested resource. The Pragma header, which specifies implementation-specific directives that might apply to any agent along the request/response chain. The Proxy-Authenticate header, which specifies that the client must authenticate itself to a proxy. The Retry-After header, which specifies a time (in seconds), or a date and time, after which the client can retry its request. The Server header, which specifies information about the originating server agent. The Set-Cookie header, which specifies cookie data that is presented to the client. The Trailer header, which specifies that the indicated header fields are present in the trailer of a message that is encoded with chunked transfer-coding. The Transfer-Encoding header, which specifies what (if any) type of transformation has been applied to the message body. The Upgrade header, which specifies additional communications protocols that the client supports. The Vary header, which specifies the request headers that are used to determine whether a cached response is fresh. The Via header, which specifies intermediate protocols to be used by gateway and proxy agents. The Warning header, which specifies additional information about that status or transformation of a message that might not be reflected in the message. The WWW-Authenticate header, which specifies that the client must authenticate itself to the server. Contains protocol headers associated with a request or response. Initializes a new instance of the class. Gets all header names (keys) in the collection. An array of type containing all header names in a Web request. Gets the number of headers in the collection. An indicating the number of headers in a request. Gets or sets the specified request header. A instance containing the specified header value. The request header value. This instance does not allow instances of . Gets or sets the specified response header. A instance containing the specified header. The response header value. The length of is greater than 65535. This instance does not allow instances of . Gets or sets the specified response header. The specified response header. The name of the specified request header. Removes the specified header from the collection. The name of the header to remove from the collection. is null. is a restricted header.-or- contains invalid characters. Returns an enumerator that can iterate through the instance. Returns .An enumerator that can iterate through the instance. This method is obsolete. The representation of the collection.